std::expm1

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Defined in header <cmath>
float       expm1( float arg );		(since C++11)
double      expm1( double arg );		(since C++11)
long double expm1( long double arg );		(since C++11)
double      expm1( Integral arg );		(since C++11)

Computes the e (Euler's number, 2.7182818) raised to the given power arg, minus 1. This function is more accurate than the expression std::exp(arg)-1 if arg is close to zero.

[edit] Parameters

arg

-

floating point value

[edit] Return value

earg
-1

If the result is too large for the underlying type, range error occurs and HUGE_VAL is returned.

[edit] See also

exp	returns e raised to the given power (ex) (function)
exp2 (C++11)	returns 2 raised to the given power (2x) (function)